2,891 research outputs found
Epitaxial ferromagnetic FeSi/Si(111) structures with high-quality hetero-interfaces
To develop silicon-based spintronic devices, we have explored high-quality
ferromagnetic FeSi/silicon (Si) structures. Using low-temperature
molecular beam epitaxy at 130 C, we realize epitaxial growth of
ferromagnetic FeSi layers on Si (111) with keeping an abrupt interface,
and the grown FeSi layer has the ordered phase. Measurements of
magnetic and electrical properties for the FeSi/Si(111) yield a magnetic
moment of ~ 3.16 /f.u. at room temperature and a rectifying
Schottky-diode behavior with the ideality factor of ~ 1.08, respectively.Comment: 3 pages, 3 figure
Magnetic switching by spin torque from the spin Hall effect
The spin Hall effect (SHE) generates spin currents within nonmagnetic
materials. Previously, studies of the SHE have been motivated primarily to
understand its fundamental origin and magnitude. Here we demonstrate, using
measurement and modeling, that in a Pt/Co bilayer with perpendicular magnetic
anisotropy the SHE can produce a spin transfer torque that is strong enough to
efficiently rotate and reversibly switch the Co magnetization, thereby
providing a new strategy both to understand the SHE and to manipulate magnets.
We suggest that the SHE torque can have a similarly strong influence on
current-driven magnetic domain wall motion in Pt/ferromagnet multilayers. We
estimate that in optimized devices the SHE torque can switch magnetic moments
using currents comparable to those in magnetic tunnel junctions operated by
conventional spin-torque switching, meaning that the SHE can enable magnetic
memory and logic devices with similar performance but simpler architecture than
the current state of the art
The role of frictional work in tribological behavior of polyamide 66 composites containing rice bran ceramics particles or glass beads
In this study, we investigated tribological behavior of polyamide 66 (PA66) composites containing rice bran ceramics (RBC) particles or glass beads (GBs) under a wide range of contact pressures and sliding velocities, and discussed the role of the frictional work in the behavior. The volume fractions of the fillers were 8 and 26 vol%. The friction coefficients of pure PA66 showed the increasing tendency with the Pv values. In contrast, those of the PA66/RBC composites showed approximately no change, and those of the PA66/GB composites slightly decreased with increasing Pv value. The surface temperatures of the materials increased with increasing frictional work. The maximum temperature of pure PA66 and the PA66 composite with 26 vol% RBC particles exceeded 80 °C, which were higher than the glass transition temperature of PA66 resin. Pure PA66 exhibited a decrease in specific wear rate with increasing frictional work even as a change of the wear mode. This change was considered to be caused by softening of the resin because of high frictional work. In contrast, the specific wear rates of the PA66 composites with the RBC particles or GBs were much lower (<0.5× 10−8 mm2/N) compared with pure PA66 at low frictional work (<1.3 MJ/(m2∙s)). At high frictional work (>1.4 MJ/(m2∙s)), the PA66 composites with the RBC particles showed relatively high specific wear rates (0.6–1.0 × 10−8 mm2/N) because of high surface temperature
Finger Motion Classification by Forearm Skin Surface Vibration Signals
The development of prosthetic hand systems with both decoration and motion functionality for hand amputees has attracted wide research interests. Motion-related myoelectric potentials measured from the surface of upper part of forearms were mostly employed to construct the interface between amputees and prosthesis
MgO barrier-perpendicular magnetic tunnel junctions with CoFe/Pd multilayers and ferromagnetic insertion layers
The authors studied an effect of ferromagnetic (Co20Fe60B20 or Fe) layer
insertion on tunnel magnetoresistance (TMR) properties of MgO-barrier magnetic
tunnel junctions (MTJs) with CoFe/Pd multilayer electrodes. TMR ratio in MTJs
with CoFeB/MgO/Fe stack reached 67% at an-nealing temperature (Ta) of 200
degree C and then decreased rapidly at Ta over 250 degree C. The degradation of
the TMR ratio may be related to crystallization of CoFe(B) into fcc(111) or
bcc(011) texture result-ing from diffusion of B into Pd layers. MTJs which were
in-situ annealed at 350oC just after depo-siting bottom CoFe/Pd multilayer
showed TMR ratio of 78% by post annealing at Ta =200 degree C.Comment: 12 pages, 4 figure
The optimum distance from electrode to the atrial wall in pacing the atrium with floating electrode of single pass VDD pacemaker — the shorter distance fails pacing
Modelling of auroral electrodynamical processes: Magnetosphere to mesosphere
Research conducted on auroral electrodynamic coupling between the magnetosphere and ionosphere-atmosphere in support of the development of a global scale kinetic plasma theory is reviewed. Topics covered include electric potential structure in the evening sector; morning and dayside auroras; auroral plasma formation; electrodynamic coupling with the thermosphere; and auroral electron interaction with the atmosphere
Estimation of phosphorus emissions in the upper Iguazu basin (Brazil) using GIS and the MoRE Model
Pollution emissions into the drainage basin have direct impact on surface water quality. These emissions result from human activities that turn into pollution loads when they reach the water bodies, as point or diffuse sources. Their pollution potential depends on the characteristics and quantity of the transported materials. The estimation of pollution loads can assist decision-making in basin management. Knowledge about the potential pollution sources allows for a prioritization of pollution control policies to achieve the desired water quality. Consequently, it helps avoiding problems such as eutrophication of water bodies. The focus of the research described in this study is related to phosphorus emissions into river basins. The study area is the upper Iguazu basin that lies in the northeast region of the State of Paraná, Brazil, covering about 2,965 km² and around 4 million inhabitants live concentrated on just 16% of its area.
The MoRE (Modeling of Regionalized Emissions) model was used to estimate phosphorus emissions. MoRE is a model that uses empirical approaches to model processes in analytical units, capable of using spatially distributed parameters, covering both, emissions from point sources as well as non-point sources. In order to model the processes, the basin was divided into 152 analytical units with an average size of 20 km². Available data was organized in a GIS environment. Using e.g. layers of precipitation, the Digital Terrain Model from a 1:10000 scale map as well as soils and land cover, which were derived from remote sensing imagery. Further data is used, such as point pollution discharges and statistical socio-economic data. The model shows that one of the main pollution sources in the upper Iguazu basin is the domestic sewage that enters the river as point source (effluents of treatment stations) and/or as diffuse pollution, caused by failures of sanitary sewer systems or clandestine sewer discharges, accounting for about 56% of the emissions. Second significant shares of emissions come from direct runoff or groundwater, being responsible for 32% of the total emissions. Finally, agricultural erosion and industry pathways represent 12% of emissions. This study shows that MoRE is capable of producing valid emission calculation on a relatively reduced input data basis
LL5β: a regulator of postsynaptic differentiation identified in a screen for synaptically enriched transcripts at the neuromuscular junction
In both neurons and muscle fibers, specific mRNAs are concentrated beneath and locally translated at synaptic sites. At the skeletal neuromuscular junction, all synaptic RNAs identified to date encode synaptic components. Using microarrays, we compared RNAs in synapse-rich and -free regions of muscles, thereby identifying transcripts that are enriched near synapses and that encode soluble membrane and nuclear proteins. One gene product, LL5β, binds to both phosphoinositides and a cytoskeletal protein, filamin, one form of which is concentrated at synaptic sites. LL5β is itself associated with the cytoplasmic face of the postsynaptic membrane; its highest levels border regions of highest acetylcholine receptor (AChR) density, which suggests a role in “corraling” AChRs. Consistent with this idea, perturbing LL5β expression in myotubes inhibits AChR aggregation. Thus, a strategy designed to identify novel synaptic components led to identification of a protein required for assembly of the postsynaptic apparatus
Meissner effect in honeycomb arrays of multi-walled carbon nanotubes
We report Meissner effect for type-II superconductors with a maximum Tc of 19
K, which is the highest value among those in new-carbon related
superconductors, found in the honeycomb arrays of multi-walled CNTs (MWNTs).
Drastic reduction of ferromagnetic catalyst and efficient growth of MWNTs by
deoxidization of catalyst make the finding possible. The weak magnetic
anisotropy, superconductive coherence length (- 7 nm), and disappearance of the
Meissner effect after dissolving array structure indicate that the graphite
structure of an MWNT and those intertube coupling in the honeycomb array are
dominant factors for the mechanism.Comment: 6 page
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